ask: add support for default answer.

Author: weakish

README.md

@@ -69,7 +69,7 @@ line options parser code.
 In addition to #cli, CLI.K provides the #ask method. This is a very simple
 command line query method.
 
-    ans = ask "Are you nice? [Y/N]"
+    ans = ask "Are you nice? [Y/n]"
 
 Other Ruby libraries have their own take on the #ask method, and this very
 simple implementation can just as soon be overridden. No biggy. But it's nice

lib/clik/ask.rb

@@ -6,7 +6,7 @@ module Kernel
   # via the console. A prompt will be sent to $stdout,
   # if given, and the input taken from $stdin...
   #
-  #   ask "Are you happy? [Yn]"
+  #   ask "Are you happy? [Yn]" "Y"
   #
   # On the command line one would see...
   #
@@ -19,10 +19,15 @@ module Kernel
   # The ask method would return "Y".
   #
   # Returns [String]
-  def ask(prompt=nil)
+  def ask(prompt=nil, default_answer=Y)
     $stdout << "#{prompt}"
     $stdout.flush
-    $stdin.gets.chomp!
+    ans = $stdin.gets.chomp!
+    if ans == ''
+      default_answer
+    else
+      ans
+    end
   end
 
 end